Ore mill



Patented Mar. 28, 1944 UNITED STATES PATENT OFFICE ORE MILL Frank J.Haverland, Deadwood, S. Dak. Application November 19, 1941, Serial No.419,799

4 Claims.

This invention relates to a complete grinding, jigging, classifying andfroth flotation unit, which can be additionally employed as anamalgamator by the addition of quick silver or mercury.

It is a primary aim of the invention to pro-- vide a grinder whichproduces comminution with a minimum of power due to the elimination ofpower losses caused by stress on pins, pivots, gears or bearings; bysubstantially eliminating abrasive slip, extreme agitation of highly viscous pulp, and hydraulic and mechanical shock; by reducing energydissipation due to vibration; by eliminating excessive grinding byclassifying the ore immediately after it is crushed; and by utilizingunavoidable turbulence and agitation to produce the jigging andflotation operation.

Still a further aim of primary importance in the invention is to providea mill having ringshaped grinding dies, one of which is movable in agyrating motion so that its engaging surface will roll on the grindingsurface of the other, fixed die, and means for exerting pressure toforce the movable die against the fixed die and which is arranged sothat its center of gravity is above the center of the contact point ofthe movable die.

Still another aim of the invention is to provide a grinding mill whereinthe gyratory motion of the movable die will produce hydraulic pressurefor drawing the ore to be ground into a position between the engagingfaces of the die, and for expelling the ground ore inwardly and into ajig bed and the pulp outwardly and into a classifying chamber.

Still another aim of the invention is to provide a mill having agyrating shaft and die and which are so constructed that the gyratorymotion of the shaft is utilized for pumping the pulp upwardly and intothe flotation zone of the mill.

Other objects and advantages of the invention will hereinafter becomemore fully apparent from the following description of the drawings,which illustrate a preferred embodiment of the invention, and wherein:

Figure 1 is a side elevational view, partly in section of the grindingmill,

Figure 2 is an enlarged cross sectional view of the mill takensubstantially along a plane as indicated by the line 2-2 of Figure 1,

Figure 3 is an enlarged central sectional view, partly in elevation of aportion of the lower part of the mill,

Figure 4 is an enlarged vertical sectional view, partly in sideelevation showing the connection of the crank and gyratory shaft, and

Figure 5 is a diagrammatic view indicating the center of gravity of theforce which is exerted on the movable die for holding it in positionagainst the fixed die.

Referring more particularly to the drawings, wherein like referencecharacters designate like or corresponding parts throughout thedifferent views, l0 designates generally a mill which includes aclassifying and flotation tank, designated generally ll, having arestricted substan-, tially flat bottom l2 provided with a centralopening l3.

A fixed, ring-shaped grinding die l4 rests on and is suitably secured tothe bottom l2 and is provided with an opening l5 which registers withthe opening I3. Die I4 is provided with a substantially flat upper,grinding surface I surrounded by an upwardly projecting flange ll. Abovethe tank II is disposed a suitably supported bearing I8 in which isjourn aled a substantially perpendicular shaft 19. A pulley 20 is keyedto the upper end of the shaft l8 and a driven belt 2| is trained overthe pulley 20 for revolving the shaft l9. Any suitable driving means,not shown, can be provided for actuating the belt 2|. As best seen inFigure 4, the shaft i9 is provided with a crank arm 22 at its lower endwhich projects laterally therefrom. A lever 23 is provided with abifurcated portion 24 in which the crank arm 22 is disposed. Thebifurcated portion 24 is connected at its free end to the free end ofthe crank arm 22 by means of a pivot pin 25. The opposite end of thelever 23 projects laterally from-the shaft IS, in the opposite directionto the arm 22, and said last mentioned end is provided with an openingwhich extends perpendicularly therethrough and which forms a bearing 26which is eccent'rically disposed relatively to the axis of the shaft I9.It will thus be readily obvious that the lever 23 is mounted to swing ina vertical plane.

An elongated shaft 21 has a restricted stem 28 at its upper end which isjournaled in the bearing 26. A head or plate 29 is mounted at theopposite, lower end of the shaft 21 and is reinforced by means ofgussets 30, as best seen in Figures 2 and 3. A movable ring-shapedgrinding die 3| is detachably secured to the under side of the head 28in any suitable manner as by means of bolts 32. The opening 33 of thedie 3| is disposed above the opening l5 and is closed at its top by theplate 29.

The under side of the die 3| forms its Erindinll face 34 which isadapted to engage the grinding face IS. The axis of the die H issubstantially in alinement with the axis of the shaft l3 so that theaxis of the shaft 21, as best seen in Figure 1, is disposed at an anglethereto. Consequently, the die 3| will be tilted, as best seen in Figure3, so that only a portion of its face 34 will be in contact with theportion of the face it at any one time. The grinding face 34 is inclinedoutwardly and upwardly at an angle so that the contacting portionthereof will engage substantially flush against the portion of thegrinding face it on which it rests.

A weight 35 is secured to th shaft 21 and equally disposed therearound.The weight 35 is disposed above and near the tank. ii and preferablycomprises a container 35 having a removable cover 31 which is adapted tobe filled with ore or other available material for weighting the shaft21 to hold the contacting portion of the grinding face 34 flush againstthe portion of the grinding face it, on which it rests.

The tank includes a conical shaped lower portion 38 which forms theclassifying zone thereof, and an annular upper portion 39 which formsthe flotation zone thereof. A froth launder 43 is disposed around. andabove the open top of the tank I The froth launder 4B is in the form ofa trough, the inner wall of which is formed by the upper part of thetank I and the outer wall of which extends to a level above the top ofthe tank II. An inverted cone shaped member 4| is supported centrally ofand in the upper part of the tank H by means of brackets 42 and extendssubstantially above thetop f the tank and terminates at its bottomslightly below the upper edge of the tank. A longer cone shaped member43 is mounted in the tank I I in an inverted position and beneath theconical member 4| and is likewise supported by brackets 42, attached tothe tank. The restricted upper end of the conical member 43 extendsslightly into the enlarged lower end of the cone 4| from which it isspaced. The enlarged, lower end of the cone 43 terminates above thelevel of the upper die 3| and is spaced from the wall of the conicalportion 38. The shaft 21 extends loosely through the cones 4| and Q3 andis adapted to gyrate therein.

A plurality of air pipes 44 extend into the tank H and open fordischarge adjacent to the grinding surfaces of the dies I4 and 3| andbeneath the cone 43. A tailings outlet 45 formed of extensible tubesections, projects upwardly and outwardly from the tank II and isadapted tov discharg into a trough or other suitable conduit 43. v

A funnel shaped member 4! is fastened to the bottom it beneath andaround the opening I31 to form a jig chamber which is provided with arestricted passage 48 which extends from its restricted lower end andwhich forms a concentrate outlet. A screen 49 is disposed across theopening l3 and supports a plurality of pebbles in the openings I to forma jig bed 50 and a millwater conduit 5| extends upwardly through thejigbed 5|) and opens into the space formed by the opening 33. A jigwater conduit 52 discharges into the jig chamber 41.

Referring to Figure 5, a circle A indicates the position of the centerof the weight 35, when at rest, and the dotted line a. indicates itscenter of gravity. The circle B indicates the location of the center ofthe weight 35 when displaced by centrifugal force due to the gyratorymotion of the shaft 21 and the dotted line indicated by b indicates thecenter of gravity thereof. The point C indicates the center of thecontacting portion posed directly over the contacting portion of the Igrinding faces so as to remove all gravity strain from the bearings 25,in one direction relatively thereto, and for removin centrifugal strainon said bearings, from the other direction, so that the bearings impartpower input by circular motion only.

The ore to be ground is preferably fed through the top of cone 4| anddescends downwardly on the'outer side of the cone 43, as indicated bythe arrows 53, to be admitted to the portions of the engaging faces l6and 34, which are out of contact. The gyratory motion of the die 3icauses it to roll in a circle on the grinding face it for grinding theore between the contacting portions of the faces l5 and 34. The lever 23allows the shaft 2i and the die 3| to move upwardly to ride over piecesof ore which it does not crush. Mill water is admitted to the tank llthrough conduit 5|, as indicated by the arrows 54, and flows outwardlybetween the faces i5 and 3d and into the tank H to maintain a continuoussupply of water thereto. The portion of the grinding face 34, moving outof contact with the face l5, creates a hydraulic suction which draws theparticles of ore into position between the faces l6 and 34; the portionof the face 33 moving into engagement with the face it produces ahydraulic pressure which tends to force the comminuted ore inwardly andinto the jig bed 53 while this pressure and the pressure of the Waterfrom the conduit 5| forces the pulp outwardl and into the tank The airadmitted through pipes 53 aerates the pulp and moves upwardly throughthe cone 43, as indicated by the dotted arrows 55. The gyratory movementof the shaft 2! in the cone 43 produces a pumping action forconveying'the air bubbles, carrying the pulp, upwardly and over the topof the cone 43 where the froth flows outwardly and into the frothlaunder 40. The water and tailings pass downwardly on the outer side ofthe cone 43 and the tailings are carried off through the conduit 45.Water is admitted through the jig water conduit 52, as indicated by thearrows 56, and is drawn upward ly through the jig bed 50 by the positiveand negative pressures set up by the upward and downward movement of thedie 3|, caused by it riding over the particles ofore which are notcrushed. This likewise tends todraw in the heavier ground particles andforce the underweight and undersize ore particles outwardly and alsoagitates the particles in the jig bed 55 to cause them to passdownwardly therethrough and through the concentrate outlet 58, fromwhich the concentrates can beremoved. The rib or flange N forms a guidefor the die 3| to keep it centered relatively to the die M.

The apparatus could also be used for dry grinding by enclosing the unitsin a suitable chamber so that by means of a vacuum fan the fineclassified dust could be drawn out as produced. Also, the apparatuscould be used for crushing intermediate sizeore to a smaller size forball or mil] feed, with or without classification and either dry or inwater.

The crushing unit can be used without the weight 35 by providing asuitable thrust bearing and heavy spring.

Various other modifications and changes are contemplated and mayobviously be resorted to, provided they fall within the spirit and scopeof the invention as hereinafter defined by the appended claims, as onlya preferred embodiment of the invention has been disclosed.

I claim as my invention:

1. An ore grinding mill having coacting dies one of which is carried bya gyratory shaft, a rotatable driving element provided with a crank arm,a U-shaped lever in the bifurcation of which said crank arm is receivedso that the lever will turn with the element and crank arm, meansvpivoting each leg of the lever to the crankarm, said lever at anopposite end having an eccentric bearing opening, and said gyratoryshaft having a portion extending into said eccentric bearing openingwhereby the latter shaft will be gyrated through rotation of the leverand element.

2. An ore grinding mill comprising a fixed die, a gyratable shaftextending upwardly from above the center of said die, a movable diehaving a downwardly open central recess connected to the lower end ofthe shaft, a driven rotary shaft concentric with the fixed die, a crankpivotally connected to the rotary shaft, said first-mentioned shafthaving its upper end journaled in the crank and eccentrically disposedrelatively to the driven shaft for gyrating the movable die when therotary shaft is revolved, said movable die engaging the upper surface ofthe fixed die, means extending through the fixed die and into the recessto supply fluid thereto, means for urging the movable die and shaftdownwardly, said dies be ing ring-shaped, a liquid containing tank inthe bottom of which said dies are disposed, and a jig bed locatedcentrally of the fixed die, said tank being provided with an outletbeneath the Jig bed, the gyrating movement of the movable die relativelyto the fixed die producing hydraulic currents adapted to concentrateheavy particles of ore, being ground by the dies, toward the Jig bed andexpelling the underweight and undersized particles of the ore outwardlyand into the liquid tank.

3. An ore grinding mill comprising a fixed die, a gyratable shaftextending upwardly from above the center of said die, a movable diehaving a downwardly open central recess connected to the lower end ofthe shaft, a driven rotary shaft con-,

centric with the fixed die. a crank pivotally connected to the rotaryshaft, said first-mentioned shafthavins itsupperendjournaledinthecrankand eccentrically disposed relatively to the driven shaft for gyratingthe movable die when the rotary shaft is revolved, said movable dieengaging the upper surface of the fixed die, means ex- .tending throughthe fixe'd die and into the recess to supply fluid thereto, means forurging the movable die and shaft downwardly, said dies beingring-shaped, a liquid containing tank in the bottom of which said diesare disposed, a jig bed located centrally of the fixed die, said tankhaving an outlet below the jig bed forming a jig chamber, the particlesof ore after being ground by the dies being adapted to be directed intothe jig bed, said crank being arranged to permit upward and downwardmovement of the first-mentioned shaft and movable die to permit themovable die to ride over particles of are not crushed thereby. and saidupward and downward movement of the movable die producing positive andnegative pressures in the ig bed and jig chamber.

4. An ore grinding mill comprising a fixed die, a gyratable shaftextending upwardly from above the center of said die, a movable diehaving a downwardly open central recess connected to the lower end ofthe shaft, a driven rotary shaft concentric with the fixed die, a crankpivotally connected to the rotary shaft-said first-mentioned shafthaving its upper end joumaled in the crank and eccentrically disposedrelatively to the driven shaft for gyrating the movable die when the 1-0tary shaft is revolved, said movable die engaging the upper surface ofthe fixed die, means extending through the fixed die and into the recessto supply fluid thereto, means for urging the movable die and shaftdownwardly, said dies being ring-shaped, a classifying tank in thebottom of which said dies are disposed, means for sup- P 81118 9. liquidto the tank between the dies. said tank being provided with superposedinverted conical members through which the firstmentioned shaft extends,means for admitting air ,into the tank for directing pulp dischargedfrom said first-mentioned shaft in the lower conical member functioningto pump the pulp upwardly andintothefiotationzoneofthetank.

FRANK J. RIVER-LAND.

